treewalk

(ns clj-async-tests.core
  (:require [clojure.core.async :as async
             :refer [go chan >! <! >!! <!! timeout close! thread alts! alts!!]]))

(defn walk [t]
  (cond (nil? t)
        nil
        :else
        (let [[l v r] t]
          (concat (walk l) [v] (walk r)))))

(defn awalk-blocking [t c]
  (cond (nil? t)
        nil
        :else
        (let [[l v r] t]
          (do
            (awalk-blocking l c)
            (>!! c v)
            (awalk-blocking r c)))))

(defn awalk-background [t c]
  ;; TODO implementation here is tripping me up probably
  (cond (nil? t)
        nil
        :else
        (let [[l v r] t]
          (do
            (awalk-background l c)
            (>! c v)
            (awalk-background r c)))))

(def t [[nil 1 nil] 2 [[nil 4 nil] 3 nil]])

(comment

; no channel
(prn (walk t))

; blocking reads
(let [c (chan)]
  (thread (awalk-blocking t c))
  (prn (<!! c))
  (prn (<!! c))
  (prn (<!! c))
  (prn (<!! c)))

; thread + alts
(let [c (chan)]
  (thread (awalk-blocking t c))
  (thread (while true
            (let [[v ch] (alts!! [c])]
              (println "Read" v "from" ch))))
  nil)

; FIXME doesn't work
(let [c (chan)
      newc (go (awalk-background t c))]
  (<!! (go (<! newc)))
  (close! newc)
  )
)